David,

You bring up a good point. For those who do not Disconnect
their Coax Cable from their Radios when they are not in-use.

A device like the MFJ-956 can serve a purpose in that it simply
allows the user to switch the Antenna's Coax Cable from the
Radio's Antenna Input to Ground.

Also, the MFJ-956 has a "By-Pass" Switch Position and can
be switched-out when it proves to be in-effective for any
specific frequency and circumstance that one encounters.

Summary :
Three Uses for the MFJ-956 Shortwave Antenna Pre-Selector / Tuner :
[ Applies to most Pre-Selectors and Antenna Tuners ]

1 - IN-USE - Use the MFJ-956 when it appears to work
using your Ears as your "It's Working" Meter = Improves
your ability to Listen to the Radio and Hear a Signal.

2 - BY PASSED - Switch the MFJ-956 Out of the Circuit
[BYP] "By Passed" when your Ears (your "It's Working"
Meter) tell you that it is not doing anything to improve
your ability to Listen to the Radio and Hear a Signal.

3 - GROUNDED - Switch the MFJ-956 to Ground [GND]
when the Radio is turned "Off" and Not-In-Use to help
protect the Radio from nearby Lightening Strikes and
ESD build-up on your Antenna.


just my two cents worth - iane ~ RHF
..
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